This invention has relation to hair cutting appliances for automatically cutting substantially all of the hair extending from the head of a customer to a uniform length and for automatically disposing of the cut-off hair ends by use of a vacuum.
It is known to use a suction tube to extend the hair from the scalp for the purpose of cutting it at a desired length. See U.S. Pat. No. 1,331,218 to Severson, granted in February of 1920; U.S. Pat. No. 4,000,562 to Alevras, granted in January of 1977; U.S. Pat. No. 4,005,526 to Clay, granted in February of 1977; and U.S. Pat. No. 4,030,196 to Koiwa et al, granted in June of 1977.
In the patent to Severson, a vacuum is applied to cause the hair to be drawn up against reciprocating shear blades within a casing. A gauge foot is provided to position the shear blades a desired distance from the scalp. A space is provided between the tips of the shear blades and the casing so that some of the hair can pass between the shear blades and the casing, and this hair is severed by the shear blades as the appliance is moved along. This structure, patented in 1920, has never found acceptance. Most of the hair drawn into the casing will hit against the back of the shear blades and will not pass between them and the casing so that a tangle will develop, and the appliance will have to be used at a very slow speed indeed to keep the hair on the back of the shear blade from being pinched and caught and then pulled out by the roots to the great discomfort of the customer. Further, there is no positive means of inducing the hair shafts which do pass between the shear blades and the casing to move between the tips of the blades to be severed. Instead, the mass of hair caught behind the shear blades will tend to keep the hair shafts passing up into the casing from getting back to position where they can be sheared by the blades.
The patent to Alevras discloses a casing to which a vacuum is applied to stand the hair on end straight away from the scalp, and slots are provided at intervals along the casing to allow scissors to be used to clip off the hair. This is obviously a painstaking and laborious method of cutting the hair, and because of the presence of the slots, there will be no effective suction to hold the cut hair shafts away from the scalp. These hair shafts will tend to fall back toward the scalp and impede the progress of adjacent uncut hair shafts to find their position in the casing so that they too can be cut. It would appear from the disclosure of the invention, that the casing must be completely removed from the hair each time and then brought back in order to pick up and position those uncut shafts which will be the only shafts to feel the full effect of the suction.
In the patent to Clay, a razor blade is brought down against the hair which is held in position away from the head by a vacuum tube 12. The vacuum tube and razor are positioned a desired distance away from the scalp by a graduated rule 23. The patent recites that the hair is cut off by moving the razor blade across the end of the vacuum tube. This device suffers from the deficiency that there is no positive vacuum action on the portion of the hair shafts from the scalp to the end of the vacuum tube. Thus as soon as a hair shaft is cut to the desired length, it will tend to fall back toward the scalp thus tending to impede the progress of other uncut hair shafts toward and into the vacuum tube. Further, as the razor blade comes across the end of the tube, the vacuum is cut off, thus insuring that the cut hair shafts fall back toward the scalp to impede the operation of the device. Here again, it would appear that the vacuum tube cannot be moved smoothly along the scalp for continuous operation but must be withdrawn from the vicinity of the scalp and moved back toward it again to try to pick up hair which will not feel an effective suction from a tube positioned from 1" to 2" away from the scalp.
The necessarily intermittent operation of the structure of the Clay and Alevras patents renders them incapable of accomplishing the purpose of the present invention.
The patent to Koiwa et al discloses a typical razor cutcomb device in conjunction with a vacuum attachment to remove cut hair particles. The device must be moved forward to cut and backward to reposition the razor with respect to the hair many, many times in order to achieve the desired effect. Each time the device is moved forward, the hair shafts pass between the teeth of a comb to properly position them so they can be effectively cut off by the razor blade or "cutting edge 22". As seen or suggested in FIGS. 1, 3 and 4 of the Koiwa et al patent, the positioning or angle of attack of the cutting edge or razor blade can be changed to determine the minimum length of hair to be cut, but there is no positive means, other than the suction, to shear off the hair ends by continuous action while passing the device across the scalp. This patent disclosure does not contemplate the combination of vacuum with the action of a barber's shear.
The general idea of attaching a vacuum cleaner hose to a barber's shear is shown in U.S. Pat. No. 3,295,200 to Padgett et al, granted in January of 1967. This disclosure contemplates the use of a barber's shear in the regular manner, but provides a nearby suction point to carry cut hair particles away. It only demonstrates the broad concept of disposing of cut hair particles as they are cut, which concept is also disclosed in the Severson patent.
The patents discussed above were discovered in a preliminary search of the prior art. Applicant and those in privity with him know of no closer art and know of no art which anticipates the claims presented herewith.